Optical fiber connectors (“connectors”) are devices used to optically connect one optical fiber to another, or to connect an optical fiber to another device such as an optical transmitter or an optical receiver. An optical fiber cable typically carries the optical fiber, which has relatively high-index core section in which most of the light is carried, and a surrounding relatively low-index cladding section that surrounds the core. A ferrule in the connector supports a bare end section of the optical fiber. The bare end section has a polished end face that coincides with a planar front face of the ferrule. The connector and the optical fiber cable constitute a cable assembly.
An important property of a connector is its ability to provide an efficient optical connection with the optical fiber of another connector, i.e., an optical connection whereby the optical loss (also called “insertion loss”) from the light passing out of one fiber end face and into the other fiber end face is minimal. This efficiency is referred to in the art as the “coupling efficiency.” A misalignment of the end faces of the two optical fibers supported by the two connectors is one of the main sources of insertion loss. Since most of the light traveling in an optical fiber is confined to the core, the couple efficiency between two connectors depends in large measure on the amount of offset between the cores. This offset can be due to a core-to-ferrule error, i.e., an offset between the location of the core of the optical fiber and the true center of the ferrule.
Ideally, the cores of the optical fibers supported by respective connectors are perfectly axially aligned to maximize the coupling efficiency. In practice, however, there is almost always some amount of core-to-ferrule eccentricity error. It would be advantageous therefore to reduce the core-to-ferrule eccentricity error on a ferrule-by-ferrule basis to improve the coupling efficiency of connectors.